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Biomedical subjects

M Sheppard

Publications and source records attributed to M Sheppard.

At least 19 recordsLinked to original sources
PubMed1992

Restriction enzyme maps for equine adenovirus 1 genome.

Physical maps were constructed for the genome of equine adenovirus 1 (EAV1) using the restriction enzymes; DraI, EcoRV, NotI and SfiI. The total size of the EAV1 genome was 34.4 kb estimated by comparison with known DNA standards and the polarity of the fragment order, with respect to the left and right molecular ends, was determined by hybridization with known regions of the human adenovirus 2 (HAV2) genome.

Adenoviridae↗
PubMed1992

Infectious laryngotracheitis virus growth, DNA replication, and protein synthesis.

The polypeptides associated with infection of primary chicken kidney (CK) cells with infectious laryngotracheitis virus (ILTV) were examined by metabolic labelling with [35S]methionine and SDS-PAGE. Polypeptide synthesis was followed over the first 24 h post-infection (p.i.) as this was shown to be the period of viable virus production. A total of 16 ILTV encoded or induced polypeptides were identified using metabolic labelling. The use of inhibitors of protein and DNA synthesis in conjunction with metabolic labelling and viral DNA replication studies enabled a cascade pattern of gene expression, similar to that of herpes simplex virus type 1 (HSV-1), to be established for ILTV. Representatives of alpha, beta, gamma 1 and gamma 2 classes of genes were identified. In contrast to infection with HSV types 1 and 2, which leads to a rapid inhibition of total host cell polypeptide synthesis, ILTV infection of CK cells did not result in a complete inhibition of cellular protein synthesis, with only a small number of host cell polypeptides absent from infected cells.

Animals↗
PubMed1992

Characterization of the avian adenovirus penton base.

A portion of the fowl adenovirus 10 (FAV-10) penton base gene was located within a Sau3A genomic DNA fragment by the combination of a plasmid expression library and colony immunoassays with rabbit anti-FAV-10-sera. The coding portion of the sequence contained in the expression vector was mapped to a 11.6-kb Bg/II fragment and more precisely mapped to the right-hand end of the 11.6-kb fragment at map units 37.7 to 41.3. Nucleotide sequence analysis of the region revealed an open reading frame of 1575 bp with translation of the sequence producing a polypeptide of 525 amino acids in length. The polypeptide predicted from the open reading frame would have a molecular weight of 57.4 kDa. Analysis of the amino acid sequence revealed an overall homology of 41.8% with the human adenovirus 2 (HAV-2) penton base. However, a region near the center of the polypeptide (amino acids 219 to 311) showed a significantly greater level of homology to the HAV-2 penton base (71%). Time course experiments using mRNA confirmed that this gene is expressed at late times postinfection. Upon probing genomic DNA from other FAV serotypes the penton base coding region hybridized to all six different serotypes tested, indicating a relatively conserved DNA sequence among a variety of FAVs.

Amino Acid Sequence↗
PubMed1992

The association of germ cell tumours of the testis with sarcoid-like processes.

Sarcoid-type pulmonary lymphadenopathy associated with testicular cancer is a rare condition which has been previously reported in only 14 cases. Earlier case reports have failed to distinguish between generalized sarcoidosis as opposed to a local granulomatous reaction to tumour. We describe a further 8 cases of the association and provide strong supportive evidence for systemic sarcoidosis in 5 of our patients. In 3 of our patients with systemic sarcoidosis there was coexisting testicular cancer requiring additional treatment. We therefore advise caution in the interpretation of the clinical and histological findings in these patients, and recommend thorough investigation of all such cases.

Adult↗
PubMed1991

Gallid herpesvirus 1 (infectious laryngotracheitis virus): cloning and physical maps of the SA-2 strain.

Clones representing 90% of the genome of Gallid herpesvirus 1 (infectious laryngotracheitis virus; ILTV) were obtained and used in hybridization experiments to construct EcoRI, KpnI amd SmaI physical maps. The genome was 155 kilobase pairs (kbp) and comprised of a long unique sequence (120 kbp) and a short unique sequence (17 kbp) bounded by repeat sequences each of 9 kbp. An unrelated second pair of repeat sequences was located at 0.67 and 0.88 map untis. A terminal repeat of the unique long region (UL) was also detected, but no isomerization of UL was detected.

Animals↗
PubMed1991

In vitro activity of cefpodoxime, a new oral cephalosporin, compared with that of nine other antimicrobial agents.

The in vitro activity of the compound RU-51746, the sodium salt of cefpodoxime (which is administered orally as the ester cefpodoxime proxetil) was compared with that of other commonly used oral antibiotics against a selection of clinical isolates of common bacteria from patients with urinary tract, soft tissue and respiratory tract infections. RU-51746 was found to inhibit 90% of Enterobacteriaceae at less than 1 mg/l; pneumococci, pyogenic streptococci (Lancefield groups A, C and G) and Streptococcus agalactiae were almost all inhibited by concentrations of less than 0.06 mg/l; Haemophilus influenzae (including beta-lactamase producers) were inhibited by less than 1 mg/l; 90% of Branhamella catarrhalis were inhibited at less than 2 mg/l. Activity against Acinetobacter spp. and staphylococci was variable and enterococci were all resistant.

Acinetobacter↗
PubMed1991

Nucleotide sequence of the gene encoding infectious laryngotracheitis virus glycoprotein B.

The nucleotide sequence of the infectious laryngotracheitis virus (ILTV) gene encoding the 205K complex glycoprotein (gp205) was determined. The gene is contained within a 3-kb EcoRI restriction fragment mapping at approximately map coordinates 0.23 to 0.25 in the UL region of the ILTV genome and is transcribed from right to left. Nucleotide sequence analysis of the DNA fragment identified a single, long open reading frame capable of encoding 873 amino acids. The predicted precursor polypeptide derived from this open reading frame would have a calculated Mr of 98,895 Da and contains nine potential glycosylation sites. Hydropathic analysis indicates the presence of an amino terminal hydrophobic sequence and hydrophobic carboxyl terminal domain which may function as a signal peptide and a membrane anchor sequence, respectively. Comparison of the predicted ILTV gp205 protein sequence with those of other herpesviruses revealed a significant sequence similarity with gB-like glycoproteins. Extensive homology was observed throughout the molecule except for the amino and carboxyl termini. The high homology in predicted primary and secondary structures is consistent with the essential role of the gB family of proteins for viral infectivity and pathogenesis.

Amino Acid Sequence↗
PubMed1990

Somatostatin receptors are present in small-cell but not in non-small-cell primary lung carcinomas: relationship to EGF-receptors.

Sixteen primary human lung tumours were analysed for their content of somatostatin receptors using receptor autoradiography with somatostatin-28 and somatostatin octapeptide analogues as radio-ligands. Two out of 4 small-cell lung carcinomas were somatostatin receptor-positive, with a high density of homogeneously distributed receptors on tumour tissue only. Somatostatin receptors were characterized in one of the tumours in homogenate binding assay as saturable, high-affinity binding sites (KD = 0.53 nM) with a number of sites (Bmax) equivalent to 189 fmoles/mg protein. These sites were specific for somatostatin, since only biologically active somatostatin analogues but not unrelated peptides showed high-affinity binding. Both receptor-positive patients had limited disease; furthermore, the small-cell lung carcinoma patient with the longest survival was receptor-positive, while the one with the shortest survival was receptor-negative. None of the 12 non-small-cell lung carcinomas (5 squamous carcinomas, 7 adenocarcinomas) contained somatostatin receptors. For comparison, epidermal growth factor receptors were found in all non-small-cell lung carcinomas. Neuroendocrine features (synaptophysin, chromogranin, neuron-specific enolase, protein gene product 9.5) were present in all small-cell lung carcinomas but absent in non-small-cell lung carcinomas. Given the receptor-mediated action of somatostatin in other neuroendocrine tumours, these data may have a bearing on the clinical application of somatostatin analogues in patients with small-cell lung carcinomas.

Adult↗
PubMed1990

Detection of DNA from infectious laryngotracheitis virus by colourimetric analyses of polymerase chain reactions.

A combination of the polymerase chain reaction and a novel ELISA-type DNA colourimetric assay (developed from studies with a retrovirus from man) was used in a preliminary study to detect DNA from avian infectious laryngotracheitis virus. The method is sensitive, specific and easy to perform. Since it can be readily adapted for the detection of DNA from other sources it could be useful for the identification of a variety of pathogens from other species of veterinary importance.

Animals↗
PubMed1990

Insulin autoantibodies in Graves' disease--before and after carbimazole therapy.

Insulin autoantibodies (IAA) are well documented in patients with insulin-dependent diabetes (IDDM) prior to the administration of insulin and in patients with reactive hypoglycaemia--the insulin autoimmune syndrome (IAS). It has been suggested that IAA can be induced by the administration of drugs containing sulphydryl groups, such as carbimazole, and they have been frequently described in Graves' disease. An alternative explanation is the clustering of autoantibodies in autoimmune disease. We studied 39 patients (37 females, two males, age range 14 to 61 years; mean 33.8 years) with proven Graves' disease and no previous treatment with carbimazole. Fifteen of the 39 patients had a family history of other autoimmune diseases. IAA and thyroid autoantibodies were assayed at diagnosis and monthly thereafter while on treatment with carbimazole, for up to 6 months. IAA were measured using a direct-binding solid-phase ELISA and specificity was confirmed by absorption studies using insulin covalently coupled to Sepharose beads. At diagnosis 33 of the 39 patients (85%) were positive for thyroid microsomal antibodies, 13 (33%) were positive for thyroglobulin antibodies, and 4 (10%) were positive for IAA. All IAA-positive patients had microsomal antibodies at diagnosis, and two had thyroglobulin antibodies in addition. After 4 months on carbimazole, the frequency of thyroid microsomal autoantibodies was unchanged (83%), while that of anti-thyroglobulin antibodies had fallen (8.6%). All four IAA-positive patients remained positive, and studies of binding to human, porcine and bovine insulin demonstrated that one serum, initially human insulin specific, later became cross-reactive with all three. We conclude that low titres of IAA are found in Graves' disease, and are associated with the presence of autoimmunity rather than the carbimazole. Symptomatic hypoglycaemia, however, is rare in Caucasian patients.

Adolescent↗
PubMed1990

Expression of fowl adenovirus type 10 antigens in Escherichia coli.

In an attempt to construct a genetic map of the fowl adenovirus (FAV) and to determine which viral proteins are natural immunogens in chickens and hence may be relevant to protective immunity we have constructed an expression library of FAV type 10 DNA. The genomic DNA was partially digested with the restriction endonuclease Sau3A, and this DNA was inserted into the 3' terminal end of the beta-galactosidase gene in a plasmid vector. To date, approximately 600 clones have been identified that express FAV type 10 antigens as determined by immunological screening with rabbit antisera to purified virus, including one that has amino acid homology with the 100 kDa protein of human adenovirus type 5. These antigen positive clones were found to contain DNA from FAV type 10 genome as determined by hybridisation to FAV DNA. These clones will allow the further characterisation of FAV and possibly the identification of potential vaccine molecules.

Animals↗
PubMed1990

Capillary haemangioma presenting as a lung pseudocyst.

A girl who developed a lung cyst at 24 hours of age during gentle ventilation for respiratory distress syndrome is reported. Instead of resolving as expected of a pseudocyst it continued to expand. Resection at 1 year of age showed a cyst entirely surrounded by capillary haemangioma. Aspiration of this cyst would have been dangerous.

Cysts↗
PubMed1990

Bovine herpes mammalitis virus thymidine kinase gene.

Bovine herpes mammillitis virus (BHMV) codes for a thymidine kinase (Tk), the gene for which is located in a 2.6 kb SalI restriction endonuclease fragment with a map unit of 0.2-0.32. This particular DNA fragment can transfect LTk-mouse cells and convert them to Tk+. The gene position of BHMV Tk would suggest another homologous gene map position for BHMV and herpes simplex virus (HSV).

Animals↗